Tarballs on the Beach Again?

By Stefan Marti

Tar ball at Fitzgerald Reserve.
Photo: Ron Lewis

During the last week of January, gobs of black tar began washing up on San Mateo County beaches. Certain areas, like Fitzgerald Reserve and Linda Mar in Pacifica, were closed to visitors.

As the huge tar patties washed to shore, beachgoers immediately feared the heavy storms had brought back more of the Cosco Busan oil.  “Beach Watch volunteers reported tarballs numbering in the hundreds that were the size of cow patties,” stated Shannon Lyday, Beach Watch Manager.

However, it turned out that the tarballs were unrelated to the November oil spill.  The oil was from a natural seep on the ocean floor, typed to the Monterey Formation near Point Conception.

Natural oil seeps are not uncommon in the area, especially during heavy winter storms when onshore winds and tides wash the oil ashore.  The natural seepage is minimal and usually occurs in January or February .

Some scientists speculate that the massive storms in January may have opened a natural fissure in the ocean floor.

All week, tarballs were reported from Monterey to San Francisco, and clean-up crews in yellow jumpsuits, gloves and booties were scouring San Mateo rocks and beaches with putty knives, sieves and plastic tools.

Tarball samples were sent to Department of Fish and Game labs in Rancho Cordova, where chemical analyses revealed the tarballs didn’t match the oil from the Cosco Busan spill.

Fitzgerald Park Ranger Sarah Lenz said she had not seen any oiled birds or other affected mammals at the 3-mile marine reserve. With the November spill, the oil floated on the surface, sticking to birds’ feathers, killing thousands of helpless scoters, grebes, and cormorants.